Modification of CTeeOutputPin::NonDelegatingQueryInterface for 2 input pins

I have modified project BaseClasses so now i can manage 2 pins. May be the desigion is to create 2 output pin (1 for each input pin) to set 1 input - 1 output. Output are same^ stereo picture.
Any ideas?

STDMETHODIMP
CEncOutPin::NonDelegatingQueryInterface(REFIID riid, void **ppv)
{
    CheckPointer(ppv,E_POINTER);
    ASSERT(ppv);
    *ppv = NULL;
    HRESULT hr = S_OK;
    // See what interface the caller is interested in.
    if(riid == IID_IMediaPosition || riid == IID_IMediaSeeking)
    {
    }
    else
    {
        return CBaseOutputPin::NonDelegatingQueryInterface(riid, ppv);
    }
    CAutoLock lock_it(m_pLock);
    ASSERT(m_pPosition_1 == NULL);
	ASSERT(m_pPosition_2 == NULL);
    IUnknown *pMediaPosition = NULL;
    // Try to create a seeking implementation
//    if(InterlockedExchange(&m_pParent->m_lCanSeek, FALSE) == FALSE)
	BOOL local_bool = m_pParent->m_lCanSeek;
	m_pParent->m_lCanSeek = FALSE;
	if(local_bool==FALSE)
        return E_NOINTERFACE;
    // Create implementation of this dynamically as sometimes we may never
    // try and seek. The helper object implements IMediaPosition and also
    // the IMediaSelection control interface and simply takes the calls
    // normally from the downstream filter and passes them upstream
	for(size_t local_counter=0;local_counter<m_pParent->m_pFirstInPins.size();local_counter++)
	{
		hr = CreatePosPassThru(GetOwner(),
                           FALSE,
                           (IPin *)&m_pParent->m_pFirstInPins[local_counter],
                           &pMediaPosition);
		if(pMediaPosition == NULL)
		{
//			InterlockedExchange(&m_pParent->m_lCanSeek, TRUE);
			m_pParent->m_lCanSeek = TRUE;
			return E_OUTOFMEMORY;
		}
		if(FAILED(hr))
		{
//			InterlockedExchange(&m_pParent->m_lCanSeek, TRUE);
			m_pParent->m_lCanSeek = TRUE;
	        pMediaPosition->Release();
		    return hr;
		}
		
		m_bHoldsSeek = TRUE;
		if(local_counter==0)
		{
			m_pPosition_1 = pMediaPosition;
			if(m_pPosition_1)
			{
				if(m_bHoldsSeek == FALSE)
					return E_NOINTERFACE;
				return ((CSeekingPassThru*)m_pPosition_1)->NonDelegatingQueryInterface(riid, ppv);
			}
		}
		if(local_counter==1)
		{
			m_pPosition_2 = pMediaPosition;
			if(m_pPosition_2)
		    {
	            if(m_bHoldsSeek == FALSE)
				    return E_NOINTERFACE;
		        return ((CSeekingPassThru*)m_pPosition_2)->NonDelegatingQueryInterface2(riid, ppv);
	        }
		}
	}
	
	return NonDelegatingQueryInterface(riid, ppv);
    
} // NonDelegatingQueryInterface

I tryed to implement IMediaSeeking in Filter class.
I have implemented interface request, most of functions.
When request of this interface is enabled in my Filter appears ASSERT message when creating Filter.
When request of this interface is disabled Filter hungs on seeking operation.

Why could it be?

STDMETHODIMP CEncStreamsStereoTransformationFilter::NonDelegatingQueryInterface(REFIID riid, void **ppv)
{
#ifdef INFORMATION_MESSAGE
    ::MessageBoxW(0,L"STDMETHODIMP CEncStreamsStereoTransformationFilter::NonDelegatingQueryInterface(REFIID riid, void **ppv)",L"Information",MB_ICONINFORMATION);
#endif
/*/
    if (riid == IID_IMediaSeeking)
    {
        *ppv = (IMediaSeeking*)this;
        ((IUnknown*)*ppv)->AddRef();
        return S_OK;
    }
/*/
    return CBaseFilter::NonDelegatingQueryInterface(riid, ppv);
}

In the Filter the vector queue is used

// Struct for queued samples
struct Sample
{
    DWORD dwFlags;
    IMediaSample *pINSSBuffer_1;		//	Кадр от первого входного пина
	IMediaSample *pINSSBuffer_2;		//	Кадр от второго входного пина
	IMediaSample *pOUTSBuffer_1;		//	Кадр от первого выходного пина
//	IMediaSample *pOUTSBuffer_2;		//	Кадр от второго выходного пина
    Sample(DWORD adwFlags, IMediaSample *apINSSBuffer_1, IMediaSample *apINSSBuffer_2,IMediaSample *apOUTSBuffer_1) :
		dwFlags(adwFlags), pINSSBuffer_1(apINSSBuffer_1), pINSSBuffer_2(apINSSBuffer_2), pOUTSBuffer_1(apOUTSBuffer_1) {}
    Sample() {}
};

In comments text is in Russian.
Текст в комментариях на русском языке.